Method of treating metal during cold rolling



Patented Nov. 2' 7, 1934 METHOD OF TREATING METAL DURING COLD ROLLING Gilbert H. Orozco, East Cleveland, Ohio, assignor to The Chandler Chemical Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Application December 30, 1933, Serial No. 704,795

10 Claims. (Cl. 153'-10) This invention relates to an improved method rolls and metal stock, other than by mere water of treating the contact surfaces of metal stock rinsing, unnecessary. I to be formed and of the forming rolls during Another objectis to eliminate sticking of chips the cold rolling of metal shapes. or flakes of steel or scale to the rolls or to the 5 In the cold rolling of steel the metal to be material with consequent roughening and scarf- 60 formed ispassed in cold condition through formening of the surfaces thereof. I

ing rolls and thereby bent to the desired shapes. As exemplary of the process and the manner In such operations, there is a surface slippage bein which it is practised, and with no intent to tween the outer exposed faces of the metal and limit the invention to the specific examples given,

the surfaces of the forming rolls and solutions the invention will hereinafter be described in 65 must be provided for lubrication and to prevent connection with present manufacture of autooverheating of the dies and consequent sticking mobile tire rims of the de ou tab e p of the material and dies. Again, it is necessary at ter type, the application thereof to the cold rollthe same time that the stock pass through the ing-of other steel forms for fabrication being aprolls at substantially the rim speed of the rolls parent therefrom, 7o so that relative slippage between the stock and In the manufacture of such rims, the common rolls in the direction of travel of the stock is p actice, after initially forming t e same by cold eliminated. Due to such surface slippage, in cold rolling, is to Complete the tion or fabricarolling, the surfaces of the metal are often scarfed tion by hand and also to rustproof or otherwise or roughened, unless a suitable treatment is procoat the same. One coating proce generally id d, employed consists-of polishing and cleaning the The customary practice has been to lubricate material and placing it in a, solution of ferrous the rolls and the material with oils, greases, and ph spha m fr m iron fi n about 1% of different compounds containing the same, all of phosphoric acid, and water, the solution being 25 which are generally known as soluble oils, and boiled for appr xim tWO hours and Yielding comprise, in effect, aqueous emulsions of oils and a ight gray coating to the Steel, Which Coating greases. While such lubricants are fairly efiecconsists of iron phosphate, and is strongly adtive in preventing roughening of the materials hesive. An oxidi in a t and a y g agent being formed and also roughening of the rolls, are added to the solution, usually manganese ox- 30 they are expensive and difficult to clean off of ide,so that the coating is abasic ferric phosphate, both the rolls and the material, and, in the case th ideal coating being on n i in hree of of the latter, require a two-stage cleaning procferrous to one of ferric phosphate. This treatess to prepare the work for commonly used ment is generally referred to as Parkerizing. rustproofing processes, such as by Parkerizing When the materials arecold rolled, the surface 35 or Bonderizing. For example, it is necessary is superfi a ly hardened andis somewhat difficult to clean the material with an alkali for removal t atta y t s pr ss a q e y in of the oil and thereafter subject the same to a de to Shorten e t e quired and also to elimpickling bath. Even with these lubricants there inate the sand or shot blasting steps of the "Parkis a substantial loss in rejected material which elizing p cess an r patented p om- 40 has not reacted properly to the subsequent proc-, 11101113 i w as B is p y d, e esses above mentioned or has become scarfed and latter bemg more n the nature of chemically rou hened due to im erfect lubrication, imperfect primnlg the material Preparatory to enameningcleagning or both p If either of these processes are to follow the cold rolling process, it is apparent that great care 45 fisg'g g g l i g i g 5332? 3?: j gi gfi ii must be exercised to remove oils, chemicals and other foreign matter from the metal. If alkali travel of the Stock so that additional scarfing and cleaners having free caustic are used to remove rughen1 ng results- I the surface oils, they also must be removed before An obJect of the present invention is to efiecthe parkerizingn or Bonderjzing process is 50 tively treat the surfaces of the metal Stock and fective and consequently'the material is usually the rolls in connection with the cold rolling of ubjected t water rinse; steel or other metals so as to overcome these Furthermore in the cold rolling of steel rims, deleterious effects and disadvantages. for example, the stock is driven through the forms Another object is to effect these results in a ing rolls by one of the rolls itself and if a grease 55 manner which renders subsequent cleaning of the lubricant is used, sufiicient traction is not afforded between the driving roll and stock to pass the stock through the rolls without slippage.

All of these steps subsequent to the rolling are eliminated and better cooperation of the rolls and stock during rolling is afforded by the method with which the present invention is concerned. Experiments, followed by commercial success, have demonstrated that aqueous solutions of soluble alkalies, i. e. compounds, whose solution have a pH greater than 7, are very effective for providing efilcient cooperation of the rolls. and stock in the cold rolling process and may be readily removed by rinsing in water, and consequently their use eliminates the subsequent cleaning steps. Substantially any alkalies or alkali salts that are soluble in Water may be used successfully though some have outstanding advantages over others. It should be borne in mind that as the pH increases upward from 7 the difficulty of removing the solution increases and it becomes increasingly dangerous to the workman because of its caustic properties. Furthermore, as the pH increases the necessity for pickling to remove the solution becomes more necessary. Solutions having a .pH above but close to 7 are preferable, for example, a concentrated solution of borax would have a pH of 9.2 but a less concentrated solution having a pH of from slightly above 7 to about 8 is more desirable.

Solutions of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium metasilicate and sodium tetraborate, the last of which is commonly known as borax and is defined chemically as NazB407-1OH2O, are effective in concentrations between 1 ounce per gallon, which is approximately 1% concentration, as a lower limit, and saturation as an upper limit.

The mild alkalies having no free caustic, such for example, as sodium tetraborate are the most desirable and have many advantages particularly in that they are so easily removed from the metal and rolls by water rinse and will not deleteriously affect these or the hands of the workmen who subsequently handle the material before rinsing. Borax has an additional advantage in the fact that when forced or pinched into the pores of the metal, it will not deleteriously affect the Parkerizing or Bonderizing process, regardless of the concentration in which used. The solutions above are recited in the inverse order of desirability for treatment in general in cold rolling and may be used separately or mixed, and, if desired,

with small additions of soap. For example, the

borax may be used either plain or with small additions of about four parts of soap to ninetysix parts of borax, by weight, or four parts of trisodium phosphate and four parts of soap to ninety-two parts of borax.

The borax has, in addition to the advantages above enumerated, other advantages which make it most desirable. It can be quickly and easily removed from the work; itscomplete removal is not necessary as its presence does not interfere with the subsequent Parkerizing and Bonderizing. Its use in commercial installations for a period of several months has given entire satisfaction both as to the actual results of rolling and convenience and safety in handling and the fact that it in no way deleteriously affects the forming rolls or the material or apparatus which is used in other operations on the material. Sodium hydroxide, on the other hand, requires an acid bath for removal by neutralization and cannot be rinsed outof the pores of the metal as readily by water.

As specific examples which have been found highly satisfactory in actual use but with no intent to limit the invention to the specific examples given, the following are cited:

1. An aqueous solution of Na2B407-10H2O in concentrations of from about 1 to 20% by weight, the preferable concentration being about 6%, that is, 8 ounces per gallon of solution.

2. An aqueous solution of tri-sodium phosphate in concentrations of from about 1 to 20%, the preferred concentration being about 6%, that is, about 8 ounces per gallon of solution.

3. Aqueous solution of the following composition:

It is most convenient to prepare the solution by thoroughly mixing the dry ingredients and dissolving portions of the mixture in water as required. For example, a dry mixture comprising borax 90%, tri-sodium phosphate 5% and tallow soap 5% may be thoroughly mixed dry and then dissolved in water in the proportions of about 8 I ounces of the dry mixture to each gallon of solution thus making a solution containing approximately 6% of the mixture. This, however, is also effective between the limits of 1 to 20% concentration. These solutions can be used at any convenient temperature, depending upon the solubility of the salts used, as the temperature of the lubricants is of relatively small importance in the rolling process. It is obvious, however, that higher temperatures are required when the higher concentrations are used because of the limits of solubility of the constituents at lower temperatures, the solubility being greater at the higher temperatures.

It has been found that the effect of such treatment of the stock is sufficient to substantially eliminate scarfing and roughening of the material and yet the composition used in connection with the treatment is of such consistency that it will not act to hold foreign matter, such as scale and the like, on the surfaces of the forming rolls or on the material formed.

Further, the composition may be conveniently applied in the same manner as lubricants commonly used, and either on the rolls or the metal stock. or both, before or during the forming operation so that during the forming operation the surfaces are sufficiently coated. After forming, the metal is rinsed with water to remove the alkali composition.

Having thus described my invention,

I claim:

1. The method of treating the complementary contact surfaces of metal stock to be formed and forming rolls during the cold rolling of metal shapes comprising maintaining on said surfaces in liquid condition and during the forming operation an aqueous solution of mild alkali containing substantially no free caustic and the mild alkali being in excess of any other solid contained in the solution.

2. The method of treating the complementary contact surfaces of metal stock to be formed and forming rolls during the cold rolling of metal shapes comprising maintaining on said surfaces in liquid condition and during the forming operation an aqueous solution of mild alkali containing substantially no free caustic and substantially no organic matter.

3. The method of treating the complementary contact surfaces of metal stock to be formed and forming rolls during the cold rolling of metal shapes comprising maintaining on said surfaces in liquid condition and during the forming operation an aqueous solution of mild alkali containing sub.tantially no free caustic and free from soap in excess of 25% by weight of the alkali.

4. The method of treating the complementary contact surfaces of metal stock to be formed and forming rolls during the cold rolling of metal shapes comprising maintaining on said surfaces in liquid condition and during the forming operation a non-saponaceous aqueous solution of mild alkali containing substantially no free caustic.

5. The method of treating the complementary contact surfaces of metal stock to be formed and forming rolls during the cold rolling of metal shapes comprising maintaining on said surfaces in liquid condition and during the forming operation an aqueous solution of mild alkali con taining a quantity of soap less than 20%, by weight, of the quantity of alkali.

6. The method of treating the complementary contact surfaces of metal stock to be formed and forming rolls during the cold rolling of metal shapes comprising maintaining on said surfaces during the forming operation an aqueous solution of mild alkali containing substantially-no free caustic, and soap, said solution being of from 1 to 20% concentration and the soap content, by

weight, being not in excess of 10% of the alkali content.

7. The method of treating the'complementary contact surfaces of metal stock to be formed and forming rolls during the cold rolling of metal shapes comprising maintaining on said surfaces during the forming operation an aqueous solution of mild alkali, comprising sodium tetraborate 1 to 20%, tri-sodium phosphate 0.2 to 5%, soap 0.2 to 5%.

8. The method of treating the complementary contact surfaces of metal stock to be formed and forming rolls during the cold rolling of metal shapes comprising maintaining on said surfaces during the forming operation an aqueous solution of mild alkali, comprising borax 6%, tri-sodium phosphate 0.5%, and soap 0.5%.

9. The method of treating the complementary contact surfaces of metal stock to be formed and forming rolls during the cold rolling of metal shapes comprising maintaining on said surfaces during the forming operation an aqueous solution containing sodium tetraborate as the principal solid ingredient contained in the solution.

10. The method of treating the complementary contact surfaces of metal stock to be formed and forming rolls during the cold rolling of metal shapes comprising maintaining on said surfaces during the forming operation an aqueous solution containing tri-sodium phosphate as the principal solid ingredient contained in the solution.

- GILBERT H. OROZCO. 

